Water softening and washing product and method of preparing same



Patented Oct. 1945.

UNITED stares T ziasaszs NT ems WATER SOF'IENENG AND WASHING HOT ANDME'EEQD 6F PREPARINGSAME Leonard Meiteaflhicago, 111

No Drawing. Application March 13, 1942, I

Serial No 434,477

' 16 Claims. (or

My invention relates to the preparation of new and highly useful alkalimetal phosphate compounds, particularly. sodium phosphate compounds, andto the resulting products. It is also concerned with the utilization ofsaid novel compounds for the softening of water, for the preparation ofwashing compositions for utilizatlonin the washing of clothes and thelike, and for numerous other purposes, all as more particularly and morefully pointed out hereinafter.

The novel alkali metal phosphate compounds of my invention are preparedby reacting phosphorus pentoxide or, in other words, phosphoricanhydride' (P205), preferably in the form of a powder, with a trlalkalimetal orthophosphate, particularly trisodium orthophosphate, at elevatedtemperatures but below the fusion point of the reaction mixture and alsobelow the temperatur'eof disintegration of the desired reaction product,the molal ratio of the trialkali metal orthophosphate to the phosphoruspentoxide being between approximately two and three to one.

In the preparation of my-novel reaction prod-" ucts, I have found itparticularly advantageous to utilize crystalline trisodium phosphatecontaining twelve molecules of water of crystallizaphosphorus whereupona tion. (NaaPO4J2I-I2O) and, where reference is made to molal ratios, itwill be understood that I utilize the numerical value of 380 as themolecular weight of the crystalline trlsodium phosphate.

The exact stru phosphate products hasnot yet been fully ascertained and,therefore, I deem it best and most accurate to characterize my novelproducts as reaction products of the defined reactants produced byheating under stated temperature conditions.

As I have pointed out hereinabove, the reaction mixture should not beheated to a temperature sufliciently high to fuse the reaction mixturenor, as I have stated, should it be heated to a temperaturesuflicientlyhigh to effect disintegration of the desired reaction product. The

temperature at whichthe reaction best proceeds, generally speaking, isthat corresponding to a dull red heat, and ranges to that approaching abright red 'heat. In terms of temperature values, a satisfactory rangeis from approximately 300 degrees C. to approximately 525 degrees 0.,although the temperature may vary somewhat from these values. If thereaction.mixture is ture of my novel alkali metalagent.

alkali metal orthophosphates may be utilized, and I the temperatures andtimesof reaction may be varied, within. limitations; without departingfrom the spirit of my invention.

Example 1 760 partsby weight of phosphate and 142 parts by weight ofpowdered pentoxide were mixed together liquid mixture was produced whichwas then heated to dryness at a temperature of approximately 400 for aperiod of one-half hour with periodic mixing. The resulting reactionproduct was then permitted to cool. It comprised a readily watersoluble,white crumbly or powdered material having exceptional properties as awater-softening Example 2 1140 parts by weight of. crystalline trisodiumphosphate were admixed with 142 parts by weight of phosphorus pentoxideand the reaction mix-' ture was heated, with periodic stirring ormixing, at a temperature ranging from 350 degrees C.- 450 -degrees C.for a eriod of about one hour. The resulting reaction product was areadily water-soluble white crumbly or rial which has exceptionallysatisfactory properties as a water-softening agent and for. otherpurposes as hereinafter disclosed.

heated at or above that t'emperature which I characterize as thetemperature of disintegration of the desired reaction product, thedesired reaction product appears to break down into what phosphate andthe phosphorus Example 3 950 parts'by weight of crystalline trisodiphosphate were admixed with 142 parts by weight of phosphorus pentoxidearId the reaction-mixture was heated, with periodic stirring or mixing.at a temperature ranging from 400 degrees 0.450 degrees C. for aperiodof about one hour. The resulting reaction product had properties similarto those of Examples 1 and 2.

A very satisfactory and convenient test to ascertain when the reactionbetween the trisodium crystalline trisodium degrees C.-450 degrees C.

powdered mate-' pentoxide is ,conr- 1 =p1td is to make up an aqueoussolution of the duly orthophosphoric acid, before reacting the,

. forms,- the reaction product may considered to they are reacted. Inview of the pH values which I my novel reaction products possess, theymay .particuiarly advantageously be utilized in enphosphate employedcontains free caustic soda or sodium carbonate,-which is usually thecase with the ordinary commercial trisodium phos-" phate products, Ihave found it advantageous initially to neutralize or substantiallyneutralize the line substances such as tetrasodiumflpyrophossaidfreecaustic soda or sodium carbonate, as the case may be, with aninorganic acid, particucxystalline tr'isodium phosphate with thephosphorus pentoxide On the other hand, where the crystalline trisodiumphosphate utilized ,con-, tains free disodium monohydrogenorthophosphate mmanroin'r hnd it advantageous. initially,=to admix thesaid crystalline trisodium phosphate with an alkali, preferably causticsoda,

to convert the 'disodium monohydrogen ortho- [phosphate intotrisodiumphosphate, or, alter.-

natively, with phosphoric acid to convert the di- .sodium monohydrogen'phosphate into monosodium dihydrogen phosphate before the reaction ,withthe phosphoruspentoxlde. Instead of pre-.

liminarily neutralizing the caustic soda or sodium carbonate or the likewith phosphoric acid,

the amount of phosphoric acid required may first be'ascertained and it,together with the trisodium phosphate and the phosphorus pentoxide, maybe admixed together and heated-to the reaction temperature. WhereIrefer. in the claims to preliminary neutralization of the caustic sodaor the like in the trisodium phosphate, it will be understood to coverthis and other alternative methods. My novel reaction products may beused for the.

treatment of water. and for washing purposes, for the sequestering ofcalcium and magnesium, as deflocculating agents, and for various uses inthe textile and other industries and under generally similar conditionsto those where heretofore known phosphate or polyphosphate compoundshave been employed, as, for example, in the case of the alkali metalmetaphosphatesas disclosed.

V inReissue Patent No. 19,719 and'in the case of the alkali metaltetraphosphates as disclosed in Patent No. 2,059,570; Under thesecircumstances I do not deem it necessary to enlarge upon the varioususes to and exact manner in which my novel reaction products may beplaced, such uses and the manner thereof being. inthe main. disclosed insuch patents as those mentioned here 'inabove as well as other patents.as. tor ex-- ample, Patents N08. 2,149,734; 2,092,913; 2,080,867;

Reissue No. 20,754 and the like.

My novel reaction'gproducts are, however, sharply distinguishable fromheretofore known phosphates such as those disclosed mentionedpatentsnot, only in ties; Thus, for example, whereas sodium hexaqmetaphosphate, disclosed in Reissue'Patent No.

19,719, has a slightly acid reaction .and the sodium I tetraphosphate'of Patent No. 2,059,570 has a pH ofapproximately 8.5 my, novel reactionproducts, in like'concentrations in aqueous solutions, have a-pI-I ofapproximately 9 or 9.5 to ap-' proximately 10, although the exact pHwill vary somewhat depending upon the exact molecular ratios of thereacting constituents employed and the temperature conditions underwhich in tha 510] B l their structure but also with respect to variousof their propervironments or compositions' containing varioussaponaceous materials, especially the higher, fatty acid soaps, theiralkalinity being generally similar to that of soap solutions. -Thesudsing of soaps and the stability and volume of foam are distinctlyimproved by the use of my novel phosphate reaction products. Hence, forex-' ample, they readily lend themselvesto the preparation of washingcompositions containing alkaphate, sodium carbonate, and the like as'well as saponaceous ingredients suchas the usual fatty acid soaps,typical compositions containing from 10% to 60% of my novel reactionproducts, balance, for example, soap. It will be understood, in

this connection, that such compositions may contain other alkalinematerials and/or diluent's or the like to provide dry orpowdercompositions for distribution and sale for household purposesaswell as, of course, for industrial usage.

Further evidence of the-different character of my-novel reactionproducts as compared with known phosphates or polyphosphates may benoted with respect to their behavior with aqueous solutions of diflerentchemicals. Illustrative of theseis the behavior when solutions of mynovel reaction products areadded to aqueoussolutions .of zinc acetate.In the case of my novel reaction products, the zinc acetate solutionremains clear for a substantial period of time, whereas, "aqueoussolutions of sodium hexametaphosphate or sodium tetr'aphosphate'forexample, when added 'todilute aqueous solutions of zinc acetate, formprecipitates in a relatively short period .of time. Even whenvprecipitates are formed, after the lapse of a substantial period ortime, when my novel reaction products'are utilized} such precipitateshave a diflerent character and appearonce from those which result wherethe aforementioned prior art phosphates are utilized. On

the other hand, with aqueous solutions of barium chloride, aqueoussolutions of my reaction products form precipitatessubstantiallyimmediately,

whereas with the hexametaphosphates and tetraphosphates the bariumchloride solution remains clear.

In addition'to the advantages of and distinctions betweenmy novelreaction products and those alkali metal phosphates heretofore known, afurther and very important advantageresides in the-factflthat' the costof manufacture of my novel reaction products is materially less than thecostof preparation of suchheretoiore known agents as. sodiumhexametaphosphate. s dium tetraphosphate, and-the like. Inthis generalconnection! may point out that Iregard as especially outstanding andimportant those of my reaction products which are derived fromapproximately three mole of crystallinet'risodium phosphate and one molof phosphorus pentoxide.

. Since various embodiments of m'y invention maybe made withoutdeparting from the spirit and scope thereoLin light of the guidinsspecific embodiments of principles which I have disclosed herein, it isto beunderstood thatI do not limit myself to the pointedoutinthe'claimsWhat isclaimed as new and-desired tobe protected by Letters Patent ofthe United. States is:

1. The method of'preparin'g a water-soluble product 'which comprisesheating a mixture of crystalline trisodium phosphate and phosphorus myinventionexcept as.

assaosa pentoxide, in a molal ratio of from approximately two toapproximately three mols of crystalline trisodium phosphate to one molof phosphorus pentoxide, at a reaction temperature not substantiallybelow 300 degrees C. but below the temj perature of disintegration of,the desired reaction product for a period of time suificient tosubstantially complete the reaction.

2. The method of preparing a water-soluble product whichcomprisesheating a mixture of to one mol of phosphorus pentoxide, at atemperature not substantially below 300 degrees C.

. 1 3 perature of disintegration of the desired reaction product and fora period of time suflicient to sub-- 7 stantially complete the reaction.

8. A-water-soluble product comprising-the reaction product of trisodiumphosphate and phosphorus pentoxide, in a molal'ratio of from about twoto about three rnols of trisodium phosphate to one mol of phosphoruspentoxide, at a reaction temperature notsubstantially below 300 degreesC. but below the temperature of disintegration of the .desired reactionproduct andfor a period of time sufficient to substantially complete thereaction.

,9-.- A water-soluble product comprising the reaction product ofcrystallinetrisodium phosphate and phosphorus pentoxide. in a molalratio of but below the temperature of disintegration of the desiredreaction product for a period of time sumcient to substantially completethe reaction. 4. The method of preparing a water-soluble product whichcomprises providing a crystalline.

trisodium phosphate in which any free caustic soda or sodium carbonatepresent therein is sub-' stantially neutralized with phosphoric acid,admixing the resulting trisodium phosphate with phosphorus pentoxide ina. molal ratio of approximately two to approximately three mols of thecrystalline trisodium phosphate to one mol of the phosphorus pentoxide,and heating the resulting mixture at a reaction temperature notsubstantially below 300 degrees C. but below the temperature ofdisintegration of the desired reaction product for a period of timesufllcient to substantially complete the reaction. I

5. The method of preparing a water-soluble product which comprisesproviding a crystalline trisodium phosphate in which any free causticsoda or sodium carbonate present therein is substantially neutralizedwith phosphoric acid, ad-

mixing the resulting trisodium phosphate with phosphorus pentoxidein amolal ratio of approximately two to approximately three mols of thecrystalline trisodium phosphate to one mol of the phosphorus pentoxide,and heating the resulting mixture at a temperature ranging fromapproximately 300 degrees C. to approximately 525 degrees C. for aperiod of time sufllcient to substantially complete the reaction.

6. The method of preparing a water-soluble product which comprisesproviding. a mixtureof crystalline trisodium phosphate and phosphoruspentoxide in a molal ratio oi! approximately three mols of thecrystalline trisodium phosphate to one mol of phosphorus pentoxide, andheating the resulti g mixture at a reaction temperature not 'substatially'below 300 degrees C. below the temperatureof disintegration ofthe desired reaction product for a period of time sufllcient tosubstantiallyfcompletethe reaction.

'7. Awater-soluble product comprising the reaction product ofcrystallinetrisodium phosphate and' phosphorus pentoxide, in a molalratio of from about two to about three mols of, crystalline trisodiumphosphate to one mol of phosphorus pentoxide, at a. reaction temperaturenot substantially below 300 degrees C. but below, the temfrom about twoto about three mols of crystalline trisodium phosphate to one mol ofphosphorus pentoxide, at a temperature ranging from approximately-300degrees C. to approximately .525

degrees C. and for a period of time suficient to substantially completethe reaction.

10. A water-soluble product having a pH- of the order of about 9 toabout 10 in aqueous solution and comprising the reaction product ofcrystalline trisodium phosphate and phosphorus pentoxide, in a molalratio of from about two to about three mols of crystalline trisodiumphosphate to one mol of phosphorus pentoxide, at a temperature rangingfrom approximately 300 degrees C. to approximately 525 degrees C. andfor a period of time suflicient to substantially complete the re-.

action.

11. A water-soluble product comprising the reaction product ofphosphorus pentoxide and crystalline trisodium phosphate in which anyfree cau'sticsoda or. sodium carbonate present in the trisodiumphosphate is substantially neutralized with phosphoric acid, in a molalratio of a'pproximately two to approximately three mols of thecrystalline trisodium phosphate to one mol'o! the phosphorus pentoxide,at a reaction tempera-' ture not substantially below 300 degrees Ciblltbelow the temperature of disintegration of'the desired reaction productand for a'period of time sufficient to substantially complete thereaction.

-12. A water-soluble product having a pH of the order of about 9 toabout 10 in aqueous solution and comprising the reaction product ofphosphorus pentoxide and crystalline trisodium phosphate in which anyfree caustic soda or sodium carbonate present in the trisodium phosphateis. substantially neutralized with phosphoric acid, in I a molal ratioof approximately three mols of the crystalline trisodium phosphate toone mol oi the phosphorus pentoxide, at a, reaction temperature notsubstantially below 300 degrees C. but below i the temperature ofdisintegration of the desired reaction product and for aperiod of timesuiiiat a temperature ranging from approximately' cient to substantiallycompletethe reaction.

13. A washing composition comprising an alkaline detergent material anda reaction prodnot of crystalline trisodiumphosphate and phosphoruspentoxide, in a molal ratio of from about two to about three mols ofcrystalline trisodium phosphate to one mol'of phosphorus pentoxide,

300 degrees C. to approximately 525 degrees C. and for a period of timesuflicient to substantially complete the reaction. I

14. A washing composition comprising a watersoluble soap and a reactionproduct of crystalline trisodium phosphate andphosphorus pentoxide, in amolal ratio of from about two to three mols of crystalline trisodiumphosphate to one mol of stantially complete the reaction.

3 15. The method oi preparing .a -water-soluble product which comprisesheating .a mixtureot 1 crystalline trialkali metal phosphate andpho'sphorus pentoxide, in. a molal ratio or from apv proximately two toapproximately three mole, oi 10 crystalline trialkali metal phosphate toone moi of phosphorus pentoxide, at a reaction tempera ture not substanlly below dezrees C. but below the temperature oi disintegration oi theo 2,885,9i38 phosphorus pentoxide, at a temperature not aubi desiredreaction product for a period of time sui- 1 stantiallybelow 300 degreesC. but below the temperature oidisintezi'etion of the desired reaction jproduct and for a period of time sumcient to eub ilcient tosubstantially complete the reaction.

16. .A water-soluble product comprising the reaction product oicrystalline trlalkali metal phoephoto and phosphorus'pentoxide, in amolal ratio of irom-ab'out two to about three mole of crystallinetrialkali metal phosphate to one moi of phosphorus pentoxide, at areaction temperature not substantially below 300 degrees C. but

below the temperature of disintegration of the I w desired reactionproduct and for a period of time suiiicient to substantially completethe reaction.

